Thermally Activated Delayed Fluorescent Material Based on 9,10-Dihydro-9,9-dimethylacridine Analogues for Prolonging Device Longevity

ABSTRACT

Thermally activated delayed fluorescent compounds and uses thereof are described. The thermally activated delayed fluorescent compounds are an analogues of 9,10-dihydro-9,9-dimethylacridine compounds.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit to U.S. Provisional Application No.62/209,647 filed Aug. 25, 2015, which is incorporated herein in itsentirety.

BACKGROUND OF THE INVENTION A. Field of the Invention

The present disclosure relates to an organic electroluminescence device,and electronic equipment.

B. Description of Related Art

In the past decade, much progress has been achieved in research ofOLEDs, therefore successively leading to applications to full-colordisplay such as television and mobile telephones. The organicelectroluminescent device is the light-emitting diodes device in whichholes from the anode, also electrons from the cathode are injected intothe emissive layer, then wherein holes and electrons are recombined, andexcitons are formed. According to the electron spin of the statisticallaw, singlet excitons and triplet excitons are produced at a ratio of25%:75%. Thus, in this case, the internal quantum efficiency offluorescent light emitted by a singlet exciton is limited to 25% becauseof the nonradiative decay of the spin-forbidden triplet exciton.

On the other hand, the phosphorescence-based OLEDs have been developedto address this issue, where the internal quantum efficiency can beincreased to 100% because noble-metal-based organometallic phosphorspossess emissive triplet states through performing the intersystemcrossing efficiently from the singlet excitons. However, the noblemetals are expensive and the abundances of them are very limited,moreover the blue PHOLEDs need to be further investigated to obtaindecent device longevity. Against this background, new concepts have beenconsidered for the fluorescence OLEDs with high efficiency utilizing thedelayed fluorescence, such as, triplet-triplet annihilation, which is aphenomenon of generating singlet excitons by the fusion of two tripletexcitons.

The internal quantum is just theoretically limited to 40%. EfficientOLEDs based on charge-transfer (CT) Cu(I) complexes have also attractedmuch interest in the last decade. However, high-performance blue OLEDsbased on Cu(I) complexes have not been reported, due to the poor devicereliability arising from oxidation of metal center. Therefore, in orderto achieve further internal quantum efficiency, the organic EL elementutilizing a mechanism involving other delayed fluorescence has beeninvestigated, such as, TADF (thermally activated delayed fluorescence,or thermal activation delay fluorescence). The TADF mechanism utilizesthe phenomenon that the reverse intersystem crossing from the tripletexciton to the singlet excitons can be realized when using the materialwith a small energy difference between the singlet level and tripletlevel (ΔST). The OLEDs involving this TADF mechanism are described byTaiki et al. (Nature, 2012, V. 492 volume, p. 234-238) where carbazolyldicyanobenzene (CDCB) acts as the TADF luminescent material. However,these conventional OLEDs using TADF luminescent materials suffer fromshort operation time.

SUMMARY OF THE INVENTION

The present invention provides a solution to the problems associatedwith the above-mentioned TADF luminescent material. The solution ispremised on novel organic compounds, which can function as a TADF lightemitting material that improve the luminous efficiency of thecorresponding devices. The new TADF materials may exhibit lowdegradation during the course of device operation, thereby providingstable organic electroluminescent device.

With the apparent conventional wisdom, a chemical structural change willaffect the electronic structure of the compounds, thereby affecting theoptical properties of the compounds (e.g., emission and absorptionspectra). Thus, a particular emission or absorption energy can beachieved by tuning or tailoring the chemical structure. For example,compounds bearing altered electron donating substituents or electronwithdrawing substituents generally exhibit different optical properties,including different emission and absorption spectra. In some aspects, anemission spectrum can be modified to be narrower or broader, and exhibita blue shift or a red shift, or a combination thereof, by altering,adding, or removing one or more of the substitution groups.

On the other hand, degradation of the materials during the course ofdevice operation can be significantly suppressed by optimization ofmolecule structure, and thereby longevity of device can meet the need ofmarket of them. For example, bearing donor moiety interlocked withbackbone structure, TADF emitter can facilitate formation of the stablehole, therefore relieving degradation of the emitter, and thus improvethe reliability of the device.

As described herein, a TADF composition may include one or morecompounds of the formulas:

where for each of the one or more compounds: A^(n) where n=1, 2, or 3can: 1) independently represent one or more acceptor moieties of thecompound, 2) be a substituted or unsubstituted electron-deficientmoeity, 3) contribute to the LUMO level of the compound, or anycombination of thereof. In some embodiments A^(n) can include whereA^(n) is nitrogen-containing heteroaryl group, a R^(q)MO group, where Mis C, S, P, or As, or a R^(q)SO₂ group, or any combination thereof. L₁,L₂, and L₃ can be linkage groups, that can include an (O) linker, asulfur (S) linker, a nitrogen (N) linker, a carbon (C) linker, aphosphorous (P) linker, a silicon (Si) linker, or a boron (B),preferably a carbon linker or a silicon linker. In some cases, at least,one of L₁ and L₂ are present, or both of them are present and whereas L₃may not be present. R^(m), R^(n), R^(p), and R^(q) each independentlyrepresents mono-, di-, tri, or tetra-substitution, and eachindependently represents one or more of deuterium, a halogen atom, ahydroxyl group, a thiol group, a nitro group, a cyano group, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedhaloalkyl group, a substituted or unsubstituted aralkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted amino group, a substituted orunsubstituted mono- or dialkylamino group, a substituted orunsubstituted mono- or diarylamino group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, asubstituted or unsubstituted heteroaryl group, an alkoxycarbonyl group,an acyloxy group, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof.

In a second general aspect, a light emitting device includes thecomposition of the first general aspect. In some cases, the lightemitting device includes an organic light emitting diode. In certaincases, the light emitting device is an organic light emitting diode.

In a third general aspect, a device includes the composition of thefirst general aspect or the light emitting device of the second generalaspect. The device may include, for example, a full color display, aphotovoltaic device, or a luminescent or phosphorescent display device.In some cases, the device includes an organic light emitting diode. Incertain cases, the device is an organic light emitting diode.

Additional aspects will be set forth in the description, which follows.Advantages will be realized and attained by means of the elements andcombinations particularly pointed out in the claims. It is to beunderstood that both the foregoing general description and the followingdetailed description are exemplary and explanatory only and are notrestrictive.

The following includes definitions of various terms and phrases usedthroughout this specification.

As used in the specification and the appended claims, the singular forms“a”, “an”, and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a component”includes mixtures of two or more components.

In some aspects, ranges expressed herein as from “about” one particularvalue to “about” another particular value include from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotheraspect. It will be further understood that the endpoints of each of theranges are significant both in relation to the other endpoint, andindependently of the other endpoint. It is also understood that thereare a number of values disclosed herein, and that each value is alsoherein disclosed as “about” that particular value in addition to thevalue itself. For example, if the value “10” is disclosed, then “about10” is also disclosed. It is also understood that each unit between twoparticular units are also disclosed. For example, if 10 and 15 aredisclosed, then 11, 12, 13, and 14 are also disclosed.

As used herein, the terms “optional” or “optionally” means that thesubsequently described event or circumstance can or cannot occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

Disclosed are the components to be used to prepare the compositionsdescribed herein as well as the compositions themselves to be usedwithin the methods disclosed herein. These and other materials aredisclosed herein, and it is understood that when combinations, subsets,interactions, groups, etc. of these materials are disclosed that whilespecific reference of each various individual and collectivecombinations and permutation of these compounds cannot be explicitlydisclosed, each is specifically contemplated and described herein. Forexample, if a particular compound is disclosed and discussed and anumber of modifications that can be made to a number of moleculesincluding the compounds are discussed, specifically contemplated is eachand every combination and permutation of the compound and themodifications that are possible unless specifically indicated to thecontrary. Thus, if a class of molecules A, B, and C are disclosed aswell as a class of molecules D, E, and F and an example of a combinationmolecule, A-D is disclosed, then even if each is not individuallyrecited each is individually and collectively contemplated meaningcombinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considereddisclosed. Likewise, any subset or combination of these is alsodisclosed. Thus, for example, the sub-group of A-E, B-F, and C-E wouldbe considered disclosed. This concept applies to all aspects of thisapplication including, but not limited to, steps in methods of makingand using the compositions. Thus, if there are a variety of additionalsteps that can be performed it is understood that each of theseadditional steps can be performed with any specific embodiment orcombination of embodiments of the methods.

As referred to herein, a linking atom can connect two groups such as,for example, a N and C group. The linking atom can optionally, ifvalency permits, have other chemical moieties attached. For example, inone aspect, an oxygen would not have any other chemical groups attachedas the valency is satisfied once it is bonded to two atom (e.g., N orC). In contrast, when carbon is the linking atom, two additionalchemical moieties can be attached to the carbon. Suitable chemicalmoieties include, but are not limited to, hydrogen, hydroxyl, alkyl,alkoxy, .═O, halogen, nitro, amine, amide, thiol, aryl, heteroaryl,cycloalkyl, and heterocycle.

The term “cyclic structure” or the like terms used herein refer to anycyclic chemical structure, which includes, but is not limited to, aryl,heteroaryl, cycloalkyl, cycloalkenyl, heterocycle, carbene, andN-heterocyclic carbene.

As used herein, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a broad aspect, thepermissible substituents include acyclic and cyclic, branched andunbranched, carbocyclic and heterocyclic, and aromatic and nonaromaticsubstituents of organic compounds. Illustrative substituents include,for example, those described below. The permissible substituents can beone or more, and the same or different for appropriate organiccompounds. For purposes of this disclosure, the heteroatoms, such asnitrogen, can have hydrogen substituents and/or any permissiblesubstituents of organic compounds described herein which satisfy thevalences of the heteroatoms. This disclosure is not intended to belimited in any manner by the permissible substituents of organiccompounds. In addition, the terms “substitution” or “substituted with”include the implicit proviso, that such substitution is in accordancewith permitted valence of the substituted atom and the substituent, andthat the substitution results in a stable compound (e.g., a compoundthat does not spontaneously undergo transformation such as byrearrangement, cyclization, elimination, etc.) It is also contemplatedthat, in certain aspects, unless expressly indicated to the contrary,individual substituents can be further optionally substituted (i.e.,further substituted or unsubstituted).

In defining various terms, “Z_(a),” “Z_(b),” “Z_(c),”, and “Z_(d),” areused herein as generic symbols to represent various specificsubstituents. These symbols can be any substituent, not limited to thosedisclosed herein, and when they are defined to be certain substituentsin one instance, they can, in another instance, be defined as some othersubstituents.

The term “alkyl” as used herein is a branched or unbranched saturatedhydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl,isopentyl, s-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl,dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, and the like. Thealkyl group can be cyclic or acyclic. The alkyl group can be branched orunbranched. The alkyl group can also be substituted or unsubstituted.For example, the alkyl group can be substituted with one or more groupsincluding, but not limited to, optionally substituted alkyl, cycloalkyl,alkoxy, amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, orthiol, as described herein. A “lower alkyl” group is an alkyl groupcontaining from one to six (e.g., from one to four) carbon atoms.

Throughout the specification “alkyl” is generally used to refer to bothunsubstituted alkyl groups and substituted alkyl groups; however,substituted alkyl groups are also specifically referred to herein byidentifying the specific substituent(s) on the alkyl group. For example,the term “halogenated alkyl” or “haloalkyl” specifically refers to analkyl group that is substituted with one or more halide, e.g., fluorine,chlorine, bromine, or iodine. The term “alkoxyalkyl” specifically refersto an alkyl group that is substituted with one or more alkoxy groups, asdescribed below. The term “alkylamino” specifically refers to an alkylgroup that is substituted with one or more amino groups, as describedbelow, and the like. When “alkyl” is used in one instance and a specificterm such as “alkylalcohol” is used in another, it is not meant to implythat the term “alkyl” does not also refer to specific terms such as“alkylalcohol” and the like.

This practice is also used for other groups described herein. That is,while a term such as “cycloalkyl” refers to both unsubstituted andsubstituted cycloalkyl moieties, the substituted moieties can, inaddition, be specifically identified herein; for example, a particularsubstituted cycloalkyl can be referred to as, e.g., an“alkylcycloalkyl.” Similarly, a substituted alkoxy can be specificallyreferred to as, e.g., a “halogenated alkoxy,” a particular substitutedalkenyl can be, e.g., an “alkenylalcohol,” and the like. Again, thepractice of using a general term, such as “cycloalkyl,” and a specificterm, such as “alkylcycloalkyl,” is not meant to imply that the generalterm does not also include the specific term.

The term “cycloalkyl” as used herein is a non-aromatic carbon-based ringcomposed of at least three carbon atoms. Examples of cycloalkyl groupsinclude, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, norbornyl, and the like. The term “heterocycloalkyl” is atype of cycloalkyl group as defined above, and is included within themeaning of the term “cycloalkyl,” where at least one of the carbon atomsof the ring is replaced with a heteroatom such as, but not limited to,nitrogen, oxygen, sulfur, or phosphorus. The cycloalkyl group andheterocycloalkyl group can be substituted or unsubstituted. Thecycloalkyl group and heterocycloalkyl group can be substituted with oneor more groups including, but not limited to, alkyl, cycloalkyl, alkoxy,amino, ether, halide, hydroxy, nitro, silyl, sulfo-oxo, or thiol asdescribed herein.

The terms “amine” or “amino” as used herein are represented by theformula NZ_(a)Z_(b)Z_(c), where Z_(a)Z_(b)Z_(c) are independentlyhydrogen, optionally substituted alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group asdescribed herein.

The terms “alkoxy” and “alkoxyl” as used herein to refer to an alkyl orcycloalkyl group bonded through an ether linkage; that is, an “alkoxy”group can be defined as —OZ_(a) where Z_(a) is alkyl or cycloalkyl asdefined above. “Alkoxy” also includes polymers of alkoxy groups as justdescribed; that is, an alkoxy can be a polyether such as —OZ_(a)—OZ_(b)or —OZ_(a)—(OZ_(b))_(n)—OZ_(c), where “n” is an integer of from 1 to 200Z_(a), Z_(b), and Z_(c) are each independently alkyl groups, cycloalkylgroups, or a combination thereof.

The term “alkenyl” as used herein is a hydrocarbon group of from 2 to 24carbon atoms with a structural formula containing at least onecarbon-carbon double bond. Asymmetric structures such as(AZ_(a)Z_(b))C═C(Z_(c)Z_(d)) are intended to include both the E and Zisomers. This can be presumed in structural formulas herein wherein anasymmetric alkene is present, or it can be explicitly indicated by thebond symbol C═C. The alkenyl group can be substituted with one or moregroups including, but not limited to, alkyl, cycloalkyl, alkoxy,alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone,azide, nitro, silyl, sulfo-oxo, or thiol, as described herein.

The term “cycloalkenyl” as used herein is a non-aromatic carbon-basedring composed of at least three carbon atoms and containing at least onecarbon-carbon double bound, i.e., C═C. Examples of cycloalkenyl groupsinclude, but are not limited to, cyclopropenyl, cyclobutenyl,cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl,norbornenyl, and the like. The term “heterocycloalkenyl” is a type ofcycloalkenyl group as defined above, and is included within the meaningof the term “cycloalkenyl,” where at least one of the carbon atoms ofthe ring is replaced with a heteroatom such as, but not limited to,nitrogen, oxygen, sulfur, or phosphorus. The cycloalkenyl group andheterocycloalkenyl group can be substituted or unsubstituted. Thecycloalkenyl group and heterocycloalkenyl group can be substituted withone or more groups including, but not limited to, alkyl, cycloalkyl,alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone,azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “alkynyl” as used herein is a hydrocarbon group of 2 to 24carbon atoms with a structural formula containing at least onecarbon-carbon triple bond. The alkynyl group can be unsubstituted orsubstituted with one or more groups including, but not limited to,alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether,halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiol, asdescribed herein.

The term “cycloalkynyl” as used herein is a non-aromatic carbon-basedring composed of at least seven carbon atoms and containing at least onecarbon-carbon triple bond. Examples of cycloalkynyl groups include, butare not limited to, cycloheptynyl, cyclooctynyl, cyclononynyl, and thelike. The term “heterocycloalkynyl” is a type of cycloalkenyl group asdefined above, and is included within the meaning of the term“cycloalkynyl,” where at least one of the carbon atoms of the ring isreplaced with a heteroatom such as, but not limited to, nitrogen,oxygen, sulfur, or phosphorus. The cycloalkynyl group andheterocycloalkynyl group can be substituted or unsubstituted. Thecycloalkynyl group and heterocycloalkynyl group can be substituted withone or more groups including, but not limited to, alkyl, cycloalkyl,alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl,aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone,azide, nitro, silyl, sulfo-oxo, or thiol as described herein.

The term “aryl” as used herein is a group that contains any carbon-basedaromatic group including, but not limited to, benzene, naphthalene,phenyl, biphenyl, phenoxybenzene, and the like. The term “aryl” alsoincludes “heteroaryl,” which is defined as a group that contains anaromatic group that has at least one heteroatom incorporated within thering of the aromatic group. Examples of heteroatoms include, but are notlimited to, nitrogen, oxygen, sulfur, and phosphorus. Likewise, the term“non-heteroaryl,” which is also included in the term “aryl,” defines agroup that contains an aromatic group that does not contain aheteroatom. The aryl group can be substituted or unsubstituted. The arylgroup can be substituted with one or more groups including, but notlimited to, alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl,cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester,ether, halide, hydroxy, ketone, azide, nitro, silyl, sulfo-oxo, or thiolas described herein. The term “biaryl” is a specific type of aryl groupand is included in the definition of “aryl.” Biaryl refers to two arylgroups that are bound together via a fused ring structure, as innaphthalene, or are attached via one or more carbon-carbon bonds, as inbiphenyl.

The term “aldehyde” as used herein is represented by the formula —C(O)H.Throughout this specification “C(O)” is a short hand notation for acarbonyl group, i.e., C═O.

The term “alkylamino” as used herein is represented by the formula—NH(-alkyl) where alkyl is as described herein. Representative examplesinclude, but are not limited to, methylamino group, ethylamino group,propylamino group, isopropylamino group, butylamino group, isobutylaminogroup, (sec-butyl)amino group, (tert-butyl)amino group, pentylaminogroup, isopentylamino group, (tert-pentyl)amino group, hexylamino group,and the like.

The term “dialkylamino” as used herein is represented by the formula—N(-alkyl)₂ where alkyl is as described herein. Representative examplesinclude, but are not limited to, dimethylamino group, diethylaminogroup, dipropylamino group, diisopropylamino group, dibutylamino group,diisobutylamino group, di(sec-butyl)amino group, di(tert-butyl)aminogroup, dipentylamino group, diisopentylamino group, di(tert-pentyl)aminogroup, dihexylamino group, N-ethyl-N-methylamino group,N-methyl-N-propylamino group, N-ethyl-N-propylamino group and the like.

The term “carboxylic acid” as used herein is represented by the formula—C(O)OH.

The term “ester” as used herein is represented by the formula—OC(O)Z_(a) or —C(O)OZ′, where Z_(a) can be alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl as describedherein. The term “polyester” as used herein is represented by theformula —(Z_(a)O(O)C—Z_(b)—C(O)O)_(n)— or —(Z_(a)(O)C—Z_(b)—OC(O))_(n)—,where Z_(a) and Z_(b) can be, independently, an alkyl, cycloalkyl,alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl groupdescribed herein and “n” is an integer from 1 to 500. “Polyester” is asthe term used to describe a group that is produced by the reactionbetween a compound having at least two carboxylic acid groups with acompound having at least two hydroxyl groups.

The term “ether” as used herein is represented by the formulaZ_(a)OZ_(b), where Z_(a) and Z_(b) can be, independently, an alkyl,cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, orheteroaryl group described herein. The term “polyether” as used hereinis represented by the formula —(Z_(a)O—Z_(b)O)_(n)—, where Z_(a) andZ_(b) can be, independently, an alkyl, cycloalkyl, alkenyl,cycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group describedherein and “n” is an integer of from 1 to 500. Examples of polyethergroups include polyethylene oxide, polypropylene oxide, and polybutyleneoxide.

The term “polymeric” includes polyalkylene, polyether, polyester, andother groups with repeating units, such as, but not limited to,—(CH₂O)_(n)—CH₃, —(CH₂CH₂O)_(n)—CH₃, —[CH₂CH(CH₃)]_(n)—CH₃,—[CH₂CH(COOCH₃)]_(n)—CH₃, —[CH₂CH(COO CH₂CH₃)]_(n)—CH₃, and—[CH₂CH(COO_(t)Bu)]_(n)—CH₃, where n is an integer (e.g., n>1 or n>2).

The term “halide” as used herein refers to the halogens fluorine,chlorine, bromine, and iodine.

The term “heterocycle,” as used herein refers to single and multi-cyclicnon-aromatic ring systems and “heteroaryl as used herein refers tosingle and multi-cyclic aromatic ring systems: in which at least one ofthe ring members is other than carbon. The term includes azetidine,dioxane, furan, imidazole, isothiazole, isoxazole, morpholine, oxazole,oxazole, including, 1,2,3-oxadiazole, 1,2,5-oxadiazole and1,3,4-oxadiazole, piperazine, piperidine, pyrazine, pyrazole,pyridazine, pyridine, pyrimidine, pyrrole, pyrrolidine, tetrahydrofuran,tetrahydropyran, tetrazine, including 1,2,4,5-tetrazine, tetrazole,including 1,2,3,4-tetrazole and 1,2,4,5-tetrazole, thiadiazole,including, 1,2,3-thiadiazole, 1,2,5-thiadiazole, and 1,3,4-thiadiazole,thiazole, thiophene, triazine, including 1,3,5-triazine and1,2,4-triazine, triazole, including, 1,2,3-triazole, 1,3,4-triazole, andthe like.

The term “hydroxyl” as used herein is represented by the formula —OH.

The term “ketone” as used herein is represented by the formulaZ_(a)C(O)R_(b), where Z_(a) and Z_(a) can be, independently, an alkyl,cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, orheteroaryl group as described herein.

The term “azide” as used herein is represented by the formula —N₃.

The term “nitro” as used herein is represented by the formula —NO₂.

The term “nitrile” as used herein is represented by the formula —CN.

The term “silyl” as used herein is represented by the formula—SiZ_(a)Z_(b)Z_(c), where Z_(a), Z_(b), and Z_(c) can be, independently,hydrogen atom or an alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl,alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.

The term “sulfo-oxo” as used herein is represented by the formulas—S(O)Z_(a), —S(O)₂Z_(a), —OS(O)₂Z_(a), or —OS(O)₂Z_(a), where Z_(a) canbe hydrogen atom or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,alkynyl, cycloalkynyl, aryl, or heteroaryl group as described herein.Throughout this specification “S(O)” is a short hand notation for S═O.The term “sulfonyl” is used herein to refer to the sulfo-oxo grouprepresented by the formula —S(O)₂Z_(a), where Z_(a) can be hydrogen atomor an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, or heteroaryl group as described herein. The term “sulfone” asused herein is represented by the formula Z_(a)(O)₂Z_(a), where Z_(a)and Z_(b) can be, independently, an alkyl, cycloalkyl,alkenylcycloalkenyl, alkynyl, cycloalkynyl, aryl, or heteroaryl group asdescribed herein. The term “sulfoxide” as used herein is represented bythe formula Z_(a)S(O)Z_(b), where Z_(a) and Z_(b) can be, independently,an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl,aryl, or heteroaryl group as described herein.

The term “thiol” as used herein is represented by the formula —SH.

“R”, “R₁,” “R₂,” “R₃,” . . . “R_(n),” where n is an integer or “R^(n)”or “R^(n′)” where n is an integer or character can independently possessone or more of the groups listed above. For example, if “R₁,” is astraight chain alkyl group, one of the hydrogen atoms of the alkyl groupcan optionally be substituted with a hydroxyl group, an alkoxy group, analkyl group, a halide, and the like. Depending upon the groups that areselected, a first group can be incorporated within second group or,alternatively, the first group can be pendant (i.e., attached) to thesecond group. For example, with the phrase “an alkyl group comprising anamino group,” the amino group can be incorporated within the backbone ofthe alkyl group. Alternatively, the amino group can be attached to thebackbone of the alkyl group. The nature of the group(s) that is (are)selected will determine if the first group is embedded or attached tothe second group.

A structure of a compound may be represented by a formula:

where n is a digit or character, and can be understood an equivalent toa formula:

That is, R^(n) is understood to represent five independent substituents,R^(n)(a), R^(n)(b), R^(n)(c), R^(n)(d), R^(n)(e). By “independentsubstituents,” it is meant that each R^(n) substituent can beindependently defined. For example, if in one instance R^(n)(a) ishalogen, then R^(n)(b) is not necessarily halogen in that instance.

A structure of a compound may be represented by a formula:

which can be understood an equivalent to a formula:

where n is typically an integer and R^(n) is as defined above. That is,A^(n) where n is an integer of 1, 2, or 3 is understood to represent oneto three independent acceptors, A¹, A², A³. By “independentsubstituents,” it is meant that each A substituent can be independentlydefined.

where Z is any structure herein and the squiggly line represents a pointof connection between two compounds.

Compounds described herein may contain “optionally substituted”moieties. In general, the term “substituted,” whether preceded by theterm “optionally” or not, means that one or more hydrogens of thedesignated moiety are replaced with a suitable substituent. Unlessotherwise indicated, an “optionally substituted” group may have asuitable substituent at each substitutable position of the group, andwhen more than one position in any given structure may be substitutedwith more than one substituent selected from a specified group, thesubstituent may be either the same or different at every position.Combinations of substituents envisioned by this invention are preferablythose that result in the formation of stable or chemically feasiblecompounds. In is also contemplated that, in certain aspects, unlessexpressly indicated to the contrary, individual substituents can befurther optionally substituted (i.e., further substituted orunsubstituted).

The present disclosure can be understood more readily by reference tothe following detailed description and the Examples included therein.Before the present compounds, devices, and/or methods are disclosed anddescribed, it is to be understood that they are not limited to specificsynthetic methods unless otherwise specified, or to particular reagentsunless otherwise specified, as such can, of course, vary. It is also tobe understood that the terminology used herein is for the purpose ofdescribing particular aspects only and is not intended to be limiting.Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing, example methodsand materials are now described.

DETAILED DESCRIPTION OF THE INVENTION

The thermally activated delayed fluorescent compounds of the presentinvention provide solutions to short operation time in optical devices.The solution is premised on analogues of9,10-dihydro-9,9-dimethylacridine compounds. The compounds can improveboth the luminescent efficiency and operational stability of a TADFdevice. Furthermore, the compounds of the present invention may exhibitlow degradation during the course of device operation, and thereforefacilitate and enhance the longevity of the corresponding TADF device.These and other features of thermally activated delayed fluorescentmaterials will be described in further detail.

A. Thermally Activated Delayed Fluorescent Compounds

As described herein, a composition may include one or more compounds ofthe formulas:

A^(n) can independently represent one or more acceptor moieties of thecompound, where n is 1 to 3, and contribute to the LUMO level of thecompound. In some embodiments, A^(n) is an electron-deficient aromaticgroup. Non-limiting examples of A include:

R^(q), R⁷, and R⁸ can each independently be a hydrogen atom, a deuteriumatom, a halogen atom, a hydroxyl group, a thiol group, a nitro group, acyano group, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted haloalkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,an amino group, a mono- or dialkylamino group, a mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof. Insome embodiments, A is a nitrogen-containing aromatic ring orsubstituted nitrogen-containing aromatic ring. In a preferredembodiment, A is:

where R^(q) is defined above.

L₁, L₂, and L₃ can be linkage groups, and can include an oxygen (O)containing group, a sulfur (S) containing group, a nitrogen (N)containing group, a carbon (C) containing group, a phosphorous (P)containing group, a silicon (Si) containing group, or a boron (B)containing group. In some embodiments, L₁, L₂ and L₃ can eachindependently be:

where R, R₁ and R₂ each independently represents a hydrogen atom,deuterium, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, an amino group, a mono- or dialkylamino group,a mono- or diarylamino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted heteroaryl group, an alkoxycarbonyl group, an acyloxygroup, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, asubstituted or unsubstituted heterocyclic group, a carbene group, or aN-heterocyclic carbene, or a combination thereof.

R^(m), R^(n), and R^(p) each independently represents mono-, di-, tri,or tetra-substitution, and each independently represents one or more ofa hydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, athiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.

Non-limiting examples of the above structures I-IV include:

where R^(q), R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and (R⁷)_(n) are eachindependently a hydrogen atom, a deuterium atom, a halogen atom, ahydroxyl group, a thiol group, a nitro group, a cyano group, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedhaloalkyl group, a substituted or unsubstituted aralkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,an amino group, a mono- or dialkylamino group, a mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof. U,U¹, and U² each independently represents N or C of an aromatic ring,with the proviso that when U, U¹ and U² present in the same structure,at least one of them is N. V, and V¹ each independently represents NR,O, S, where R can be a alkyl, cycloalkyl, aryl, heteroaryl. In someinstances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and (R⁷)_(n) are eachindependently a hydrogen atom, an alkyl group (e.g., methyl, ethyl orpropyl group), or an aromatic (e.g., phenyl) group. In some embodiments,(R⁷)_(n) includes two aromatic groups and hydrogen atoms.

In certain embodiments, structures I, II, or III can include twoacceptor moieties, and can be represented by the following generalstructures.

where L₁, L₂, R^(m), R^(n), R^(p), R^(q), A¹, and A² have beenpreviously defined, and R^(u) can represent mono-, di-, tri, ortetra-substitution, and each independently represents one or more of ahydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, athiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.Non-limiting examples of the above structures include:

where R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n) and (R⁸)_(n) are as definedabove. In some instances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n) and(R⁸)_(n) are each independently a hydrogen atom, a deuterium atom, ahalogen atom, a hydroxyl group, a thiol group, a nitro group, a cyanogroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted haloalkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,an amino group, a mono- or dialkylamino group, a mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof. U,U¹, and U² each independently represents N or C of an aromatic ring,with the proviso that when U, U¹ and U² present in the same structure,at least one of them is N. V, and V¹ each independently represents NR,O, S, wherein R represents alkyl, cycloalkyl, aryl, heteroaryl. In someinstances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n), and (R⁸)_(n) are eachindependently a hydrogen atom, an alkyl group (e.g., methyl, ethyl orpropyl group), or an aromatic (e.g., phenyl) group. In some embodiments,(R⁷)_(n) and (R⁸)_(n) include two aromatic groups with the balance ofthe substituents being hydrogen atoms.

In certain embodiments, structures I, II, or III can include threeacceptor moieties and can be represented by the following generalstructures.

where L₁, L₂, R^(m), R^(n), R^(p), R^(q), R^(u) A¹, A², and A³ have beenpreviously defined, and R^(v) can represent mono-, di-, tri, ortetra-substitution, and each independently represents one or more of ahydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, athiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.Non-limiting examples of the above structures VIII, IX, and X include:

where R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n), (R⁸)_(n), R⁹, and R¹⁰ are asdefined above. In some instances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n),(R⁸)_(n), R⁹, and R¹⁰ are each independently a hydrogen atom, adeuterium atom, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, an amino group, a mono- or dialkylamino group,a mono- or diarylamino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted heteroaryl group, an alkoxycarbonyl group, an acyloxygroup, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof. U, U¹, and U² each independently represents N or Cof an aromatic ring, with the proviso that when U, U¹ and U² present inthe same structure, at least one of them is N. V, and V¹ eachindependently represents NR, O, S, where R can be an alkyl, cycloalkyl,aryl, heteroaryl. In some instances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷,(R⁷)_(n), (R⁸)_(n), R⁹, and R¹⁰ are each independently a hydrogen atom,an alkyl group (e.g., methyl, ethyl or propyl group), or an aromatic(e.g., phenyl) group. In some embodiments, (R⁷)_(n) and (R⁸)_(n) includetwo aromatic groups with the balance of the substituents being hydrogenatoms.

In some embodiments, the compounds of the present invention can berepresented by the following general structures:

where L₁, L₂, R^(m), R^(n), R^(p), R^(q), and A^(n), have beenpreviously defined. B and B² can each be a substituted or unsubstitutedelectron-deficient aromatic group and can in combination with A^(n)contribute to the LUMO of the level of the compound. R^(s) and R^(t) caneach independently represents mono-, di-, tri, or tetra-substitution,and each independently represents one or more of a hydrogen atom, adeuterium atom, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted amino group, asubstituted or unsubstituted mono- or dialkylamino group, a substitutedor unsubstituted mono- or diarylamino group, a substituted orunsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted heteroaryl group, analkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.

Non-limiting examples of structures XI and XII are:

where R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n), (R⁸)_(n), R⁹, and R¹⁰ are asdefined above. In some instances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, (R⁷)_(n),(R⁸)_(n), R⁹, and R¹⁰ are each independently a hydrogen atom, adeuterium atom, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, an amino group, a mono- or dialkylamino group,a mono- or diarylamino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted heteroaryl group, an alkoxycarbonyl group, an acyloxygroup, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof. U, U¹, and U² each independently represents N or Cof an aromatic ring, with the proviso that when U, U¹ and U² present inthe same structure, at least one of them is N. V, and V¹ eachindependently represents NR, O, S, where R can be an alkyl, cycloalkyl,aryl, heteroaryl. In some instances, R¹, R², R³, R⁴, R⁵, R⁶, R⁷,(R⁷)_(n), (R⁸)_(n), R⁹, and R¹⁰ are each independently a hydrogen atom,an alkyl group (e.g., methyl, ethyl, or propyl group), or an aromatic(e.g., phenyl) group.

In some embodiment, each B can include one or more acceptors A^(n), andbe represented by the following general structures.

where L₁, L₂, R^(m), R^(n), R^(p), R^(q), R^(s), R^(t), R^(u), A¹, A²,and B are as previously defined. Non-limiting examples of the abovestructures XIII and XIV include:

In some embodiments, the compounds can be represented by the followinggeneral structures:

where R^(m), R^(n), R^(p), R^(q), R^(s), R^(t), and A¹ are as previouslydefined, and where L₁, L₂, L₃ and L₄ are linked directly or through alinking atom or group to A¹, and can be:

where R, R₁, and R₂ are as previously defined. Non-limiting examples ofstructures XV, XVI, and XVII include:

In some embodiments, the compositions disclosed herein include one ormore of the following:

where A¹ is as defined above. L₁, L₂, L₃, L₄, L₅, and L₆ can be linkagegroups, and can include an oxygen (O) containing group, a sulfur (S)containing group, a nitrogen (N) containing group, a carbon (C)containing group, a phosphorous (P) containing group, a silicon (Si)containing group, or a boron (B) containing group. In some embodiments,L₁, L₂, L₃, L₄, L₅, and L₆ can each independently be:

where R, R₁ and R₂ are as previously defined.

R^(a), R^(b), R^(c), R^(d), R^(e), R^(f), R^(g), R^(h), and R^(i) caneach independently represents mono-, di-, tri, or tetra-substitution,and each independently represents one or more of a hydrogen atom, adeuterium atom, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted amino group, asubstituted or unsubstituted mono- or dialkylamino group, a substitutedor unsubstituted mono- or diarylamino group, a substituted orunsubstituted alkoxy group, a substituted or unsubstituted aryloxygroup, a substituted or unsubstituted heteroaryl group, analkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.

Non-limiting examples of compounds XVIII, XIX, and XX include:

Implementations of the present invention may include one or more of thefollowing features. In some cases, for example, the polymeric groupincludes a polyalkylene, a polyether, or a polyester. In certain cases,for at least one of the compounds, at least one of the following istrue: R_(a) is fused to L₁, R_(b) is fused to L₂, R_(c) is fused to L₃,and R_(d) is fused to L₄. The composition, or a compound of thecomposition, may have a neutral charge.

In some embodiments, the thermally activated delayed fluorescentcomposition (TADF) can be compound shown herein or any mixture thereof.In certain embodiments, the thermally activated delayed fluorescentcomposition is compound 1, 2, 3, or 4 below, or any mixture thereof.

B. Method of Making Thermally Activated Delayed Fluorescent Compositions

The thermally activated delayed fluorescent compositions can be madeusing known organic synthetic methodology and exemplified in the Examplesection. In one non-limiting aspect, the thermally activated delayedfluorescent materials can be prepared using Suzuki-Miyaura reactionmethodology. A general synthetic route for the synthesis of thethermally activated delayed fluorescent compositions is shown inreaction scheme (1).

The donor portion of the TADF composition can include a leaving group(e.g., halogen (Br, I), or tosylate (OTf). The donor portion can bereacted with a diboride to form donor substituted borylated compound.The donor substituted borylated compound can then be coupled with amono- or di-halogenated acceptor portion of the TADF composition to formthe TADF compound having a donor portion and an acceptor portion. Anon-limiting example of making compounds 1-4 are shown in reactionscheme (2), shown below. Aromatic halide 5 can be reacted with adiboride to form borylated compound 6. Borylated compound 6 can then becoupled with a mono- or di-halogenated aromatic compound to formthermally activated delayed fluorescent compounds 1 and 2. In a similarmanner, aromatic halide 7 can be reacted with a diboride compound toform borylated compound 8. Borylated compound 6 can then be coupled witha mono- or di-halogenated aromatic compound to form thermally activateddelayed fluorescent compounds 3 and 4.

C. Uses of Thermally Activated Delayed Fluorescent Compounds

In some implementations, the compositions disclosed herein or blendsthereof are used as host materials for OLED applications, such as fullcolor displays. In one aspect, the compositions disclosed herein can beuseful in a wide variety of applications, such as, for example, lightingdevices. In a further aspect, one or more of the complexes can be usefulas host materials for an organic light emitting display device. Inanother aspect, the compositions disclosed herein are useful in avariety of applications, for example, as light emitting materials. In afurther aspect, the compounds can be useful in organic light emittingdiodes (OLEDs), luminescent devices and displays, and other lightemitting devices. In another aspect, the compositions disclosed hereincan be useful as, for example, host materials for OLEDs, lightingapplications, and combinations thereof. In another aspect, thecompositions disclosed herein can provide improved efficiency and/oroperational lifetimes in lighting devices. In some aspects, thecompositions disclosed herein can provide improved efficiency and/oroperational lifetimes for organic light emitting devices as compared toconventional materials.

EXAMPLES

The present invention will be described in greater detail by way ofspecific examples. The following examples are offered for illustrativepurposes only, and are not intended to limit the invention in anymanner. Those of skill in the art will readily recognize a variety ofnoncritical parameters, which can be changed or modified to yieldessentially the same results.

Materials. The materials used to make compounds 1-4 shown in reactionscheme (2) were obtained from commercial sources or made using knownorganic methods. Potassium acetate, dioxane,1,1′-Bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II)((PdCl₂-(dppf)), dppf, bis(pinacolato)diboron,2-chloro-4,6-diphenyl-1,3,5-triazine,2,4-dichloro-6-phenyl-1,3,5-triazine, tetrakis(triphenylphosphine)palladium(O), tetrahydrofuran (THF), potassium carbonate, ethyl acetate,hexane, magnesium sulfate (MgSO₄), and chloroform were obtained fromSigma-Aldrich® (USA).

Synthesis of Compounds 6 and 8

Compounds 5 and 7 were made using general organic transformationmethodology. The overall synthetic routes for compounds 5 and 7 areshown in reaction schemes (3) and (4) respectively. The reactantamounts, solvents, temperatures and time can be varied depending on theamount of compounds 5 and 7 produced and are within the generalknowledge of one skilled in the art of organic synthesis.

Referring to the reaction scheme (1), a mixture of potassium acetate(1.6 mmol), dry dioxane (3.3 mL), PdCl₂-(dppf), 13 mg, 0.016 mmol), dppf(9 mg, 0.016 mmol), bis(pinacolato)diboron (150 mg, 0.6 mmol) andcompound 5 or 7 (150 mg, 0.54 mmol) was heated and stirred under argon,at reflux for 2 h. The reaction mixture was diluted with ethyl acetate(100 mL), washed with water (50 mL), dried over magnesium sulfate andconcentrated in vacuo to a dark brown oil which was purified by flashcolumn chromatography on florisil using gradient elution (from hexane to5:95 ethyl acetate-hexane) to yield boronate 6 or 8, respectively (75mg, 54%) as colorless needles.

Synthesis of Compounds 1, 2, 3, and 4

To a solution of 2-chloro-4,6-diphenyl-1,3,5-triazine or2,4-dichloro-6-phenyl-1,3,5-triazine (2 mmol), 0.482 g of boronatecompound 6 or 8 (2.2 mmol) and 1.16 g of tetrakis(triphenylphosphine)palladium(O) (0.1 mmol) in 10 ml of THF were added dropwise, withstirring, a solution of 0.55 g of potassium carbonate (4 mmol) in 10 mLof water. Subsequently, the mixture was stirred and refluxed for 2 days.The cooled mixture was partitioned between water and ethyl acetate. Theorganic layer was separated, and the aqueous layer was extracted withethyl acetate. The combined organic layers were washed with brine, driedover Mg₂SO₄, and concentrated in vacuo. Then 100 mL of chloroform wasadded to it, the brown precipitate formed was collected by filtration,washed with 100 mL of chloroform, dried under vacuum, and the productswere obtained. The yield was around 70%.

1.-20. (canceled)
 21. A thermally activated delayed fluorescentcomposition having the general formula of:

wherein:

independently represents one or more acceptor moieties of the compoundthat contributes to LUMO level of the compound, where A^(n) isnitrogen-containing heteroaryl group, a R^(q)MO group, where M is C, S,P, or As, or a R^(q)SO₂ group, or any combination thereof; and n=1, 2,or 3, such that the compound includes a single acceptor moiety (A¹), twoacceptor moieties (A¹ and A²), or three acceptor moieties (A¹, A², andA³), and wherein each acceptor moiety is substituted with R^(q): L₁, L₂,and L₃ are each independently linkage groups comprising an oxygen (O)containing group, a sulfur (S) containing group, a nitrogen (N)containing group, a carbon (C) containing group, a phosphorous (P)containing group, a silicon (Si) containing group, or a boron (B)containing group; wherein at least one of L₁, L₂, and L₃ comprises aboron containing group; and R^(m), R^(n), R^(p) R^(q), and R^(q′) eachindependently represent mono-, di-, tri, or tetra-substitution, and eachindependently are one or more of a hydrogen atom, a deuterium atom, ahalogen atom, a hydroxyl group, a thiol group, a nitro group, a cyanogroup, a substituted or unsubstituted alkyl group, a substituted orunsubstituted haloalkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted amino group, a substituted orunsubstituted mono- or dialkylamino group, a substituted orunsubstituted mono- or diarylamino group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, asubstituted or unsubstituted heteroaryl group, an alkoxycarbonyl group,an acyloxy group, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof.
 22. The composition of claim 21, wherein L₁, L₂,and L₃ are each independently

wherein at least one of L₁, L₂, and L₃ is represented by

wherein R, R₁ and R₂ each independently represents a hydrogen atom,deuterium, a halogen atom, a hydroxyl group, a thiol group, a nitrogroup, a cyano group, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted haloalkyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aryl group, an amino group, a mono- or dialkylamino group,a mono- or diarylamino group, a substituted or unsubstituted alkoxygroup, a substituted or unsubstituted aryloxy group, a substituted orunsubstituted heteroaryl group, an alkoxycarbonyl group, an acyloxygroup, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, asubstituted or unsubstituted heterocyclic group, a carbene group, or aN-heterocyclic carbene, or a combination thereof.
 23. The composition ofclaim 22, wherein L₁ is represented by


24. The composition of claim 22, wherein two of L₁, L₂, and L₃ arerepresented by


25. The composition of claim 22, wherein each of L₁, L₂, and L₃ isrepresented by


26. The composition of claim 22, wherein in the group

R is selected from the group consisting of a substituted orunsubstituted alkyl group, a substituted or unsubstituted aryl group,and a substituted or unsubstituted heteroaryl group.
 27. The compositionof claim 21, wherein A^(n) is:

wherein R^(q′) has the same definition as R^(q).
 28. The composition ofclaim 21, wherein A^(n) is a nitrogen-containing heteroaryl groupcomprising 1 to 3 nitrogen atoms.
 29. The composition of claim 21,wherein A^(n) is

where U, U¹, and U² each independently represents N or C; with theproviso that at least one of U¹ and U² is N.
 30. The composition ofclaim 21, wherein A^(n) is


31. The composition of claim 21, wherein n is 2 and the composition hasthe general structure of:

wherein:

independently represents a second acceptor moiety of the compound thatcontributes to LUMO level of the compound, where A² isnitrogen-containing heteroaryl group, a R^(u)MO group, where M is C, S,P, or As, or a R^(u)SO₂ group, or any combination thereof; and R^(u) isa mono-, di-, tri, or tetra-substitution, and each substitution is oneor more of a hydrogen atom, a deuterium atom, a halogen atom, a hydroxylgroup, a thiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxy carbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.32. The composition of claim 21, wherein n=3, and the composition hasthe general structure of:

where:

independently represents a second acceptor moiety of the compound thatcontributes to LUMO level of the compound, where A² isnitrogen-containing heteroaryl group, a R^(u)MO group, where M is C, S,P, or As, or a R^(u)SO₂ group, or any combination thereof;

independently represents a third acceptor moiety of the compound,contributes to LUMO level of the compound, where A³ isnitrogen-containing heteroaryl group, a R^(v)MO group, where M is C, S,P, or As, or a R^(v)SO₂ group, or any combination thereof; and R^(u) andR^(v) are each independently a mono-, di-, tri, or tetra-substitution,and each substitution is one or more of a hydrogen atom, a deuteriumatom, a halogen atom, a hydroxyl group, a thiol group, a nitro group, acyano group, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted haloalkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted amino group, a substituted orunsubstituted mono- or dialkylamino group, a substituted orunsubstituted mono- or diarylamino group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, asubstituted or unsubstituted heteroaryl group, an alkoxycarbonyl group,an acyloxy group, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof.
 33. The composition of claim 21, having the generalstructure of:

where: L₃ and L₄ are each independently linkage groups comprising anoxygen (O) containing group, a sulfur (S) containing group, a nitrogen(N) containing group, a carbon (C) containing group, a phosphorous (P)containing group, a silicon (Si) containing group, or a boron (B)containing group; and R^(m), R^(n), R^(s), R^(t), each independentlyrepresents mono-, di-, tri, or tetra-substitution, and eachindependently represents one or more of a hydrogen atom, a deuteriumatom, a halogen atom, a hydroxyl group, a thiol group, a nitro group, acyano group, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted haloalkyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted amino group, a substituted orunsubstituted mono- or dialkylamino group, a substituted orunsubstituted mono- or diarylamino group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted aryloxy group, asubstituted or unsubstituted heteroaryl group, an alkoxycarbonyl group,an acyloxy group, an acylamino group, an alkoxycarbonylamino group, anaryloxycarbonylamino group, a sulfonylamino group, a sulfamoyl group, acarbamoyl group, an alkylthio group, a sulfinyl group, a ureido group, aphosphoramide group, a mercapto group, a sulfo group, a carboxyl group,a hydrazino group, a substituted silyl group, a polymeric group, or acombination thereof.
 34. The composition of claim 33, having the generalstructure:

where L₅ and L₆ are each independently linkage groups comprising anoxygen (O) containing group, a sulfur (S) containing group, a nitrogen(N) containing group, a carbon (C) containing group, a phosphorous (P)containing group, a silicon (Si) containing group, or a boron (B)containing group; and R^(a), R^(b), R^(c), R^(d), R^(e), R^(f), R^(g),R^(h), and R^(i) each independently represents mono-, di-, tri, ortetra-substitution, and each independently represents one or more of ahydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, athiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxy carbonyl group, an acyloxy group, an acylamino group,an alkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.35. A thermally activated delayed fluorescent composition having ageneral structure of:

where:

independently represents one or more acceptor moieties of the compoundthat contributes to LUMO level of the compound, where A^(n) isnitrogen-containing heteroaryl group, a R^(q)MO group, where M is C, S,P, or As, or a R^(q)SO₂ group, or any combination thereof; and n=1, 2,or 3, such that the compound includes a single acceptor moiety (A¹), twoacceptor moieties (A¹ and A²), or three acceptor moieties (A¹, A², andA³), and wherein each acceptor moiety is substituted with R^(q); and L₁and L₂ are each independently linkage groups comprising an oxygen (O)containing group, a sulfur (S) containing group, a nitrogen (N)containing group, a carbon (C) containing group, a phosphorous (P)containing group, a silicon (Si) containing group, or a boron (B)containing group; wherein at least one of L₁ and L₂ comprises a boroncontaining group; and ring B and ring B² are each independently asubstituted electron-deficient aromatic group, R^(m), R^(n), R^(p),R^(s), and R^(t) each independently represents mono-, di-, tri, ortetra-substitution, and each independently represents one or more of ahydrogen atom, a deuterium atom, a halogen atom, a hydroxyl group, athiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.36. The composition of claim 35, wherein n=2, and the composition hasthe general structure of:

wherein

independently represents a second acceptor moiety of the compound thatcontributes to LUMO level of the compound, where A² isnitrogen-containing heteroaryl group, a R^(u)MO group, where M is C, S,P, or As, or a R^(u)SO₂ group, or any combination thereof; and R^(u) isa mono-, di-, tri, or tetra-substitution, and each substitution is oneor more of a hydrogen atom, a deuterium atom, a halogen atom, a hydroxylgroup, a thiol group, a nitro group, a cyano group, a substituted orunsubstituted alkyl group, a substituted or unsubstituted haloalkylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aryl group, a substituted orunsubstituted amino group, a substituted or unsubstituted mono- ordialkylamino group, a substituted or unsubstituted mono- or diarylaminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted heteroarylgroup, an alkoxycarbonyl group, an acyloxy group, an acylamino group, analkoxy carbonylamino group, an aryloxycarbonylamino group, asulfonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthiogroup, a sulfinyl group, a ureido group, a phosphoramide group, amercapto group, a sulfo group, a carboxyl group, a hydrazino group, asubstituted silyl group, a polymeric group, or a combination thereof.37. The composition of claim 35, wherein ring B is an aryl group.
 38. Alight emitting device comprising the thermally activated delayedfluorescent composition of claim
 21. 39. The light emitting device ofclaim 38, wherein the light emitting device is an organic light emittingdiode.
 40. The light emitting device of claim 38, wherein the devicecomprises a full color display, a photovoltaic device, a luminescentdisplay device or a phosphorescent display device.